Objectives of this systematic review To assess the association of working alliance with changes in health outcomes (mental health, physical health, quality of life) in digital health interventions in any disease. To assess if different components of working alliance (bond, task, goal) have an association with changes in health outcomes (mental health, physical health, quality of life). To explore the role of the intensity of interaction in the digital health intervention (low vs. high interaction) as an effect modifier of the association of working alliance with changes in health outcomes. Website of Complementary and Integrative Digital Health, Institute of Primary Care, University of Zurich and University Hospital Zurich, Switzerland